Staff of the Robert Koch Institute for disease control takes a swap sample of mayor Christoph Spieles as part of a local corona monitoring study following an outbreak of the coronavirus disease (COVID-19) in Kupferzell, Germany, May 19, 2020, to prepare for a possible second wave of COVID-19. Marijan Murat/Pool via Reuters

Staff of the Robert Koch Institute for disease control takes a swap sample of mayor Christoph Spieles as part of a local corona monitoring study following an outbreak of the coronavirus disease (COVID-19) in Kupferzell, Germany, May 19, 2020, to prepare for a possible second wave of COVID-19. Marijan Murat/Pool via Reuters

Cans of food sit in a "Swap Box", a box where people can donate or take free food, beside a road, amid the coronavirus disease (COVID-19) outbreak in Windsor, Connecticut, U.S., May 13, 2020. REUTERS/Brian Snyder

Prisoners of war (POWs) (not in uniform), wearing protective masks amid the coronavirus disease (COVID-19) outbreak, walk during the exchange of prisoners between Ukraine and the separatist republics near near Shchastya in Luhansk region, Ukraine April 16, 2020. Yevgen Goncharenko/Pool via REUTERS

A prisoner of war (POW), wearing a protective mask amid the coronavirus disease (COVID-19) outbreak, is escorted by a serviceman of the self-proclaimed republics during the exchange of prisoners between Ukraine and the separatist republics near the Mayorsk crossing point in Donetsk Region, Ukraine April 16, 2020. REUTERS/Alexander Ermochenko

Prisoners of war (POWs), wearing a protective mask amid the coronavirus disease (COVID-19) outbreak, wait during the exchange of prisoners between Ukraine and the separatist republics near the Mayorsk crossing point in Donetsk Region, Ukraine April 16, 2020. REUTERS/Alexander Ermochenko

A prisoner of war (POW), wearing a protective mask amid the coronavirus disease (COVID-19) outbreak, is escorted by a serviceman of the self-proclaimed republics during the exchange of prisoners between Ukraine and the separatist republics near the Mayorsk crossing point in Donetsk Region, Ukraine April 16, 2020. REUTERS/Alexander Ermochenko

Servicemen of the self-proclaimed republics walk next to vehicles of OSCE Special Monitoring Mission to Ukraine during the exchange of prisoners of war (POWs) between Ukraine and the separatist republics near the Mayorsk crossing point in Donetsk Region, Ukraine April 16, 2020. REUTERS/Alexander Ermochenko

A prisoner of war (POW), wearing a protective mask amid the coronavirus disease (COVID-19) outbreak, is escorted by a serviceman of the self-proclaimed republics during the exchange of prisoners between Ukraine and the separatist republics near the Mayorsk crossing point in Donetsk Region, Ukraine April 16, 2020. REUTERS/Alexander Ermochenko

A prisoner of war (POW), wearing a protective mask amid the coronavirus disease (COVID-19) outbreak, is escorted by servicemen of the self-proclaimed republics during the exchange of prisoners between Ukraine and the separatist republics near the Mayorsk crossing point in Donetsk Region, Ukraine April 16, 2020. REUTERS/Alexander Ermochenko

A prisoner of war (POW), wearing a protective mask amid the coronavirus disease (COVID-19) outbreak, is escorted by a serviceman of the self-proclaimed republics during the exchange of prisoners between Ukraine and the separatist republics near the Mayorsk crossing point in Donetsk Region, Ukraine April 16, 2020. REUTERS/Alexander Ermochenko

A prisoner of war (POW), wearing a protective mask amid the coronavirus disease (COVID-19) outbreak, is escorted by servicemen of the self-proclaimed republics during the exchange of prisoners between Ukraine and the separatist republics near the Mayorsk crossing point in Donetsk Region, Ukraine April 16, 2020. REUTERS/Alexander Ermochenko

Prisoners of war (POWs), wearing a protective mask amid the coronavirus disease (COVID-19) outbreak, walk during the exchange of prisoners between Ukraine and the separatist republics near the Mayorsk crossing point in Donetsk Region, Ukraine April 16, 2020. REUTERS/Alexander Ermochenko

A prisoner of war (POWs), wearing a protective mask amid the coronavirus disease (COVID-19) outbreak, is escorted by servicemen of the self-proclaimed republics during the exchange of prisoners between Ukraine and the separatist republics near the Mayorsk crossing point in Donetsk Region, Ukraine April 16, 2020. REUTERS/Alexander Ermochenko

Prisoners of war (POWs), wearing a protective mask amid the coronavirus disease (COVID-19) outbreak, wait next to members of OSCE (Special Monitoring Mission to Ukraine) during the exchange of prisoners between Ukraine and the separatist republics near the Mayorsk crossing point in Donetsk Region, Ukraine April 16, 2020. REUTERS/Alexander Ermochenko

Prisoners of war (POWs), wearing a protective mask amid the coronavirus disease (COVID-19) outbreak, wait during the exchange of prisoners between Ukraine and the separatist republics near the Mayorsk crossing point in Donetsk Region, Ukraine April 16, 2020. REUTERS/Alexander Ermochenko

A member of medical staff swaps a Palestinian worker for coronavirus disease (COVID-19) testing, upon his return from Israel, outside the Israeli-controlled Tarqumiya checkpoint near Hebron in the Israeli-occupied West Bank March 26, 2020. REUTERS/Mussa Qawasma

Soccer Football - Europa League - Round of 16 First Leg - LASK Linz v Manchester United - Linzer Stadion, Linz, Austria - March 12, 2020 Manchester United's Fred swaps shirts with LASK Linz's Michael Klauss at the end of the match REUTERS/Lisi Niesner

Soccer Football - Europa League - Round of 16 First Leg - LASK Linz v Manchester United - Linzer Stadion, Linz, Austria - March 12, 2020 Manchester United's Fred swaps shirts with LASK Linz's Michael Klauss at the end of the match REUTERS/Lisi Niesner

People walk in an office in the financial centre of Canary Wharf in London, Britain March 6, 2020. Traders at the world's biggest banks are swapping their plush city centre offices to work from suburban outposts in New York and London, facing lengthy commutes as their employers attempt to reduce the disruption caused by coronavirus. REUTERS/Kevin Coombs

People walk in an office in the financial centre of Canary Wharf in London, Britain March 6, 2020. Traders at the world's biggest banks are swapping their plush city centre offices to work from suburban outposts in New York and London, facing lengthy commutes as their employers attempt to reduce the disruption caused by coronavirus. REUTERS/Kevin Coombs

People walk in an office in the financial centre of Canary Wharf in London, Britain March 6, 2020. Traders at the world's biggest banks are swapping their plush city centre offices to work from suburban outposts in New York and London, facing lengthy commutes as their employers attempt to reduce the disruption caused by coronavirus. REUTERS/Kevin Coombs

People walk in an office in the financial centre of Canary Wharf in London, Britain March 6, 2020. Traders at the world's biggest banks are swapping their plush city centre offices to work from suburban outposts in New York and London, facing lengthy commutes as their employers attempt to reduce the disruption caused by coronavirus. REUTERS/Kevin Coombs

A section of the Israeli barrier is seen in the background as a boy is silhouetted while standing in the porch of a house in the Arab-Israeli village of Baqa al-Gharbiyye, Israel February 1, 2020. Picture taken February 1, 2020. REUTERS/Ammar Awad

A carpet is seen hanging outside a family's home as a military road runs between the Arab-Israeli city of Umm al-Fahm and the Palestinian village of Anin in the Israeli-occupied West Bank near Jenin January 30, 2020. Picture taken January 30, 2020. REUTERS/Ammar Awad

A general view shows the Arab-Israeli city of Umm al-Fahm in the foreground and Wadi Ara in the background, Israel January 30, 2020. Picture taken January 30, 2020. REUTERS/Ammar Awad

A section of the Israeli barrier is seen in the Arab-Israeli village of Baqa al-Gharbiyye, Israel February 1, 2020. Picture taken February 1, 2020. REUTERS/Ammar Awad

A youth rides a bicycle next to a section of the Israeli barrier in the Arab-Israeli village of Baqa al-Gharbiyye, Israel February 1, 2020. Picture taken February 1, 2020. REUTERS/Ammar Awad

A general view picture shows the Arab-Israeli city of Umm al-Fahm in the foreground and Wadi Ara in the background, Israel January 30, 2020. Picture taken January 30, 2020. REUTERS/Ammar Awad

A general view shows the Arab-Israeli city of Umm al-Fahm in the foreground and Wadi Ara in the background, Israel January 30, 2020. Picture taken January 30, 2020. REUTERS/Ammar Awad

Palestinian men stand next to a fence which separates the Arab-Israeli city of Umm al-Fahm and the Palestinian village of Anin in the Israeli-occupied West Bank near Jenin January 30, 2020. Picture taken January 30, 2020. REUTERS/Ammar Awad

A fence separates the Arab-Israeli city of Umm al-Fahm and the Palestinian village of Anin in the Israeli-occupied West Bank near Jenin January 30, 2020. Picture taken January 30, 2020. REUTERS/Ammar Awad

Buildings in the Palestinian village of Nazlat Isa near Tulkarm in the Israeli-occupied West Bank are seen behind the Israeli barrier and from the Arab-Israeli village of Baqa al-Gharbiyye, Israel February 1, 2020. Picture taken February 1, 2020. REUTERS/Ammar Awad

A mosque is seen in the Arab-Israeli village of Baqa al-Gharbiyye, Israel February 1, 2020. Picture taken February 1, 2020. REUTERS/Ammar Awad

Buildings are seen in Arab-Israeli city of Umm al-Fahm, Israel January 30, 2020. Picture taken January 30, 2020. REUTERS/Ammar Awad

Jan 5, 2020; Miami, Florida, USA; Portland Trail Blazers guard Damian Lillard (0) displays his tattoos after swapping jerseys with Miami Heat forward Meyers Leonard (not pictured) at American Airlines Arena. Mandatory Credit: Steve Mitchell-USA TODAY Sports

Jan 5, 2020; Miami, Florida, USA; Portland Trail Blazers guard Damian Lillard (0) displays his tattoos after swapping jerseys with Miami Heat forward Meyers Leonard (not pictured) at American Airlines Arena. Mandatory Credit: Steve Mitchell-USA TODAY Sports

Japanese Foreign Minister Toshimitsu Motegi and Philippines' Foreign Affairs Secretary Teodoro Locsin Jr. swap their signed notes during a signing ceremony and press briefing after their meeting in Manila, Philippines, January 9, 2020. REUTERS/Willy Kurniawan

Jan 6, 2020; Washington, District of Columbia, USA; Washington Wizards guard Admiral Schofield (L) and Boston Celtics forward Grant Williams (R) swap jerseys after their game at Capital One Arena. Mandatory Credit: Geoff Burke-USA TODAY Sports

Soccer Football - FA Cup - Third Round - Burnley v Peterborough United - Turf Moor, Burnley, Britain - January 4, 2020 Burnley's Joe Hart swaps shirts with Peterborough United's Christy Pym after the match Action Images via Reuters/Molly Darlington

Relatives and acquaintances embrace a Ukrainian serviceman, who was exchanged during a prisoners of war (POWs) swap between Ukraine and the separatist self-proclaimed republics, during a welcoming ceremony at the Boryspil International Airport outside Kiev, Ukraine December 29, 2019. REUTERS/Valentyn Ogirenko

A Ukrainian citizen, who was exchanged during a prisoners of war (POWs) swap between Ukraine and the separatist self-proclaimed republics, embraces a relative upon the arrival at the Boryspil International Airport outside Kiev, Ukraine December 29, 2019. REUTERS/Valentyn Ogirenko

Ukraine's President Volodymyr Zelenskiy attends a ceremony to welcome Ukrainian citizens, who were exchanged during a prisoners of war (POWs) swap with the separatist self-proclaimed republics, at the Boryspil International Airport outside Kiev, Ukraine December 29, 2019. REUTERS/Valentyn Ogirenko

Relatives of Ukrainian citizens, who were exchanged during a prisoners of war (POWs) swap between Ukraine and the separatist self-proclaimed republics, wait before a welcoming ceremony at the Boryspil International Airport outside Kiev, Ukraine December 29, 2019. REUTERS/Valentyn Ogirenko TPX IMAGES OF THE DAY

Ukrainian citizens, who were exchanged during a prisoners of war (POWs) swap between Ukraine and the separatist self-proclaimed republics, and their relatives attend a welcoming ceremony at the Boryspil International Airport outside Kiev, Ukraine December 29, 2019. REUTERS/Valentyn Ogirenko

A Ukrainian serviceman, who was exchanged during a prisoners of war (POWs) swap between Ukraine and the separatist self-proclaimed republics, embraces relatives upon the arrival at the Boryspil International Airport outside Kiev, Ukraine December 29, 2019. REUTERS/Valentyn Ogirenko

Ukraine's President Volodymyr Zelenskiy attends a ceremony to welcome Ukrainian citizens, who were exchanged during a prisoners of war (POWs) swap with the separatist self-proclaimed republics, at the Boryspil International Airport outside Kiev, Ukraine December 29, 2019. REUTERS/Valentyn Ogirenko

Ukrainian citizens, who were exchanged during a prisoners of war (POWs) swap between Ukraine and the separatist self-proclaimed republics, and their relatives attend a welcoming ceremony at the Boryspil International Airport outside Kiev, Ukraine December 29, 2019. REUTERS/Valentyn Ogirenko

Ukrainian citizens, who were exchanged during a prisoners of war (POWs) swap between Ukraine and the separatist self-proclaimed republics, and their relatives attend a welcoming ceremony at the Boryspil International Airport outside Kiev, Ukraine December 29, 2019. REUTERS/Valentyn Ogirenko

A Ukrainian citizen, who was exchanged during a prisoners of war (POWs) swap between Ukraine and the separatist self-proclaimed republics, embraces a relative upon the arrival at the Boryspil International Airport outside Kiev, Ukraine December 29, 2019. REUTERS/Valentyn Ogirenko

A Ukrainian citizen, who was exchanged during a prisoners of war (POWs) swap between Ukraine and the separatist self-proclaimed republics, embraces a relative upon the arrival at the Boryspil International Airport outside Kiev, Ukraine December 29, 2019. REUTERS/Valentyn Ogirenko

A Ukrainian citizen, who was exchanged during a prisoners of war (POWs) swap between Ukraine and the separatist self-proclaimed republics, is welcomed by relatives upon the arrival at the Boryspil International Airport outside Kiev, Ukraine December 29, 2019. REUTERS/Valentyn Ogirenko

A Ukrainian serviceman, who was exchanged during a prisoners of war (POWs) swap between Ukraine and the separatist self-proclaimed republics, embraces relatives upon the arrival at the Boryspil International Airport outside Kiev, Ukraine December 29, 2019. REUTERS/Valentyn Ogirenko

A Ukrainian serviceman, who was exchanged during a prisoners of war (POWs) swap between Ukraine and the separatist self-proclaimed republics, embraces an acquaintance upon the arrival at the Boryspil International Airport outside Kiev, Ukraine December 29, 2019. REUTERS/Valentyn Ogirenko

Ukraine's President Volodymyr Zelenskiy greets a Ukrainian serviceman during a ceremony to welcome citizens, who were exchanged during a prisoners of war (POWs) swap with the separatist self-proclaimed republics, at the Boryspil International Airport outside Kiev, Ukraine December 29, 2019. REUTERS/Valentyn Ogirenko

Relatives embrace a Ukrainian serviceman, who was exchanged during a prisoners of war (POWs) swap between Ukraine and the separatist self-proclaimed republics, at the Boryspil International Airport outside Kiev, Ukraine December 29, 2019. REUTERS/Valentyn Ogirenko

Relatives of Ukrainian citizens, who were exchanged during a prisoners of war (POWs) swap between Ukraine and the separatist self-proclaimed republics, surround an aircraft during a welcoming ceremony at the Boryspil International Airport outside Kiev, Ukraine December 29, 2019. REUTERS/Valentyn Ogirenko

A Ukrainian citizen, who was exchanged during a prisoners of war (POWs) swap between Ukraine and the separatist self-proclaimed republics, embraces a relative at the Boryspil International Airport outside Kiev, Ukraine December 29, 2019. REUTERS/Valentyn Ogirenko

Ukraine's President Volodymyr Zelenskiy greets a Ukrainian serviceman during a ceremony to welcome citizens, who were exchanged in a prisoners of war (POWs) swap with the separatist self-proclaimed republics, at the Boryspil International Airport outside Kiev, Ukraine December 29, 2019. REUTERS/Valentyn Ogirenko